Calories Burned - seated rowing

Discussion in 'Hydrodynamics and Aerodynamics' started by Russ Kaiser, Jun 11, 2014.

  1. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 18, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    I'm posting this question in this forum for lack of a better place to ask. I have been rowing my aluminum boat (14 foot, sharp prow, square stern) 3 to 4 times a week for that last month in hopes that it will help me fight the battle of the bulge. Rowing is an exercise I actually enjoy so I've been sticking with it pretty well. Obviously knowing how many calories I'm burning is a curiosity on my part. It would be nice to know just to compare it to other activities.

    This is simple seated rowing, no sliding seat or sliding rig, and information related to "real" rowing and calories burned just isn't out there. I thought I would ask my brilliant friends on this forum if they knew how to approach the problem.

    I have been tracking my progress in STRAVA (GPS based fitness app) so I know how long I have been rowing during each outing, the distance traveled, the peak speed and the average speed.

    On average I have been rowing around 4.6 kph. I modeled my boat in Delftship and it looks like at a rate of 2.48 kts (4.6 kph) and loaded with my weight, my boat produces 3 lbs of resistance. I assume then that three lbs. of thrust would maintain it at 4.6 kph. Is that a correct assumption?

    Assuming the above, and if I understand the units and conversion correctly, producing 3 lbs of thrust requires about 132 watts. Here is where things get fuzzy for me. First, I know human rowing is not 100% efficient. They say a cycling human is 20 to 25 percent efficient. Would rowing be more or less?

    At any rate, does anyone have some insight to loan me here?
     
  2. upchurchmr
    Joined: Feb 2011
    Posts: 3,054
    Likes: 150, Points: 63, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    There was an extensive thread on Woodenboat on rowing (I think).
    I don't have the location.
    Have you looked using the search function?
     
  3. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 18, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Thanks, upchurchmr, I will give Wooden Boat a look.

    I searched this forum for "Calories" in the title, no hits.
     
  4. upchurchmr
    Joined: Feb 2011
    Posts: 3,054
    Likes: 150, Points: 63, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Try rowing or row boat.
    There was another thread on HPV boats (human powered) but I don't think it had that title, and was mostly about pedal driven with a little paddle wheel and some of the Hobie fin drive discussion. There was lots of information on calories with different types of drives.
     
  5. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 18, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    I waded through 3 pages of hits on this forum when I searched for "rowing" and over 7 on Wooden Boat (there Bilge forum is way out of control, BTW) and didn't really find anything specific.

    I think I have most of the information I need, but answering the question isn't a must. I will keep digging.
     
  6. upchurchmr
    Joined: Feb 2011
    Posts: 3,054
    Likes: 150, Points: 63, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    I'll try to look thru my messages to threads on Woodenboat and look for what I remembered, sorry, it won't be today.

    Marc
     
  7. johnhazel
    Joined: Jun 2008
    Posts: 250
    Likes: 5, Points: 18, Legacy Rep: 60
    Location: Michigan

    johnhazel Senior Member

    If you have access to any exercise equipment that calculates calories burned you can get a rough estimate by checking your pulse while rowing and then getting on the exercise machine and seeing what the calorie rate on the machine is when you exercise at the same heart rate. The best machine of course would be a rowing simulator.
     
  8. Russ Kaiser
    Joined: Jul 2009
    Posts: 119
    Likes: 2, Points: 18, Legacy Rep: 35
    Location: Winston-Salem, NC

    Russ Kaiser Exuberant Amateur

    Great Suggestion

    I didn't realize until you suggested this that there was a direct correlation between heart rate and calories burned. My wife has an exercise heart rate monitor that I can borrow and there seems to be plenty of sites with information that will help me get close to calculating what I'm burning.

    Thanks
     
  9. Skyak
    Joined: Jul 2012
    Posts: 1,194
    Likes: 25, Points: 38, Legacy Rep: 152
    Location: United States

    Skyak Senior Member

    Russ,
    heart rate does not correlate directly with calories burned. Sorry. A fit person's heart rate can be one fifth the rate of someone out of shape for the same work done. I suggest you consult a certified professional trainer at least -better yet a doctor. Short of that let me throw in a few things I have learned

    -rowing is a fine exercise because it activates a large number of muscles and does not shock any joints. Be careful of your lower back and do some situps to balance out your workout.
    -Crediting yourself with calories burned by exercise? That is how people get fat! It's how fat people justify getting fatter! It's chapter one in "getting fat for dummies". Ask any fitness professional. If fat is your problem, diet is the primary solution. My best advice is appetite suppression. A hundred calorie snack that suppresses your appetite for half a day is much better than any zero calorie diet drink.
    -If you want to measure progress a good one is heart rate at a particular rowing velocity. First check your heart rate at rest (average many readings) then compare that to your heart rate rowing at speed. As you get fit your heart rate will decline. When your rowing heart rate gets below a certain level, you graduate to an increased rowing speed. The heart rate monitor will have targets. You can find better plans online. A good CPT or doctor will do better yet.
    -My other advice for measurement is simple honest waist circumference. Weight is not as good a measurement because muscle is denser than fat. A man could get in dramatically better shape and still weigh about the same. Another good measurement is some bodyweight exercise -pushups, chinups, situps -how many can you do before you can't lift yourself?

    -My last advice is a little cutting edge but I am doing it and excited. There is a very good study that found 90%+ of the benefit of exercise can be achieved by exerting 'all out' for two minutes straight, just twice a week. No joke. Scientific, peer reviewed, top notch authority...

    I would be skeptical but I have heard about the virtues of 'all out' sprints from highly respected athletes for decades.
     
  10. markdrela
    Joined: Jun 2004
    Posts: 307
    Likes: 28, Points: 28, Legacy Rep: 324
    Location: MIT Aero & Astro

    markdrela Senior Member

    We're not talking about a universal correlation. We're talking about a given person at a given fitness level. In that case heart rate does correlate quite well with power output, and also correlates with VO2 uptake which indicates calorie burn rate.

    John Hazel's suggestion of "calibrating" your heart rate/power relation on an instrumented exercise machine is a good one. For each sustained power level you should see your heart rate stabilize at some value. This assumes that you have adequate cooling (e.g. with a fan), and that you are below your anaerobic threshold, so that reaching thermal and biochemical equilibrium is possible.

    Note however that how the exercise machine converts the measured energy (power*time) to calories burned is uncertain, and may also include the basic metabolic rate which you probably don't want to count. It's better to use only the machine's measured power, and do the energy/calorie conversion yourself by assuming some efficiency like 25% or 30%.
     
  11. Skyak
    Joined: Jul 2012
    Posts: 1,194
    Likes: 25, Points: 38, Legacy Rep: 152
    Location: United States

    Skyak Senior Member


    I don't know what to say. You say I am wrong then you go on to list examples recognizing I am right.

    Heart rate does not correlate to to power output, calorie burn, or VO2. Examples; Increased heart rate based on fear, sexual attraction, embarrassment... Is it done? Yes it is done to give some desired measurement based on readily available data -noting that it is inaccurate. The studies use percentage of maximum heart rate -which is based on VO2 measurement -for correction.

    VO2 IS a good measure for calories burned.

    I never said that John's suggestion was bad. For the same individual doing roughly the same exercise under similar conditions it would be reasonable to assume that at equal heart rate they are burning the same calories. The gym machine is just a rough estimate and using heart rate does not add much error.

    But assuming heart rate correlates to calorie burn is wrong, with negative consequences, and there are much better and accurate uses of heart rate. The first positive aspect of regular exercise will be a reduction in heart rate both at rest and for a given exertion with faster recovery. Based on your correlation his exercise is rapidly declining in value when the opposite is true -he is seeing tangible evidence of improving health!

    If heart rate correlates to calorie burn then you would get equations like "20 minutes of watching **** earns me a twinky!"
     
  12. gonzo
    Joined: Aug 2002
    Posts: 14,583
    Likes: 701, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The problem with using heart rate as a measurement standard is that as he gets in shape, his heart rate will decrease for the same amount of work done. A good measure of physical fitness is heart recovery rate.
     
  13. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 196, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

  14. johnhazel
    Joined: Jun 2008
    Posts: 250
    Likes: 5, Points: 18, Legacy Rep: 60
    Location: Michigan

    johnhazel Senior Member

    This is true gonz It is important to do the tests (boat and gym erg) within a few days to avoid having a change in conditioning between the tests. It is also important to minimize other differences too. For example, temperature, wind cooling, rest and food.The idea here is to get a power output estimate that a regular guy can do.

    The original post asked for a way to compare other activity's calorie burning to rowing. The easiest way is to measure heart rate for all the activities in question. As long as it is the same persons heart rate being measured and you have reduced the other variables, the calorie burning rate will be close for activities that cause the same heart rate.

    If he wants to actually measure the amount of calories burned, the the gym ergronomer would help by giving a measured output power.
     

  15. johnhazel
    Joined: Jun 2008
    Posts: 250
    Likes: 5, Points: 18, Legacy Rep: 60
    Location: Michigan

    johnhazel Senior Member

    If it is the same individual and you have made good efforts to reduce other variables, two activities that cause the same heart rate are going to be close in their calorie burn rate.
     
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.